Microsoft today stopped providing Windows 7 Home Basic, Windows 7 Home Premium, and Windows 7 Ultimate licenses to original equipment manufacturers (OEMs), including its PC partners and systems builders. This means you’ll only be able to buy a computer running Windows 7 as long as stock lasts.

The only exception will be business computers running Windows 7 Professional, which will continue being sold for at least another year. The Windows Lifecycle chart for sales below summarizes the important dates we know.

The two asterisks for Windows 7 Professional in the last column point to an important note: “Microsoft will provide one year of notice prior to the end of sale date.” Since Microsoft hasn’t updated the chart yet with a new date, we can safely say Windows 7 Professional will still be sold until October 31, 2015, if not longer.

So if you still want a Windows 7 computer, for whatever reason, expect to be paying for Windows 7 Professional. As inventory runs out, you may even be charged a premium for a “business machine,” because OEMs know they can get away with it.

It’s also worth noting that Mainstream Support for Windows 7, including for Windows 7 Professional, will end sooner than that, on January 13, 2015. Microsoft could decide to extend Mainstream Support, so as to avoid selling it with only Extended Support offered, though it has not given any indication yet it will do so.

For those who don’t know, Mainstream Support includes free incident support, warranty claims, fixes for non-security as well as security bugs, plus design changes and feature requests. Extended Support consists solely of security updates.

Microsoft’s main goal now is to get Windows 10 out the door. That being said, it wants to keep its current customers, especially enterprises and businesses, satisfied. After all, one day they will be considering upgrading from Windows 7 or Windows 8 to the latest and greatest.